Brendan O'Neill is editor of the online magazine spiked and is a columnist for the Big Issue in London and The Australian in, er, Australia. His satire on environmentalism, Can I Recycle My Granny and 39 Other Eco-Dilemmas, is published by Hodder & Stoughton. He doesn't
tweet.

Hold the front page! Some Catholic schools in Britain are teaching their pupils Catholic ideas! Yes, according to shocking newspaper reports, secondary schools run by the Catholic Church are teaching children that "traditional marriage" is superior to "gay marriage". In assemblies, the children have been told that marriage between a man and a woman is a "natural institution" which brings "huge value to society". Some of these Catholic schools have even invited their Catholic children to sign a Catholic-leaning petition against the creation of same-sex marriage, on the basis that it would be a "profoundly radical" change.

What is the world coming to when, in the 21st century, in daylight hours, in an educational institution, the offspring of Catholics can openly be taught Catholic values? This madness must end!

Keep your hair on. This open-mouthed alarm at Catholic schools for promoting the virtues of traditional marriage is a bit like being shocked to discover that a Friends of the Earth summer camp teaches children BS about the eco-End of Days or that a Jewish school says the Torah is a good read. Catholic schools have a certain amount of leeway to teach the Catholic view on life, sex and relationships. If they didn't, then they wouldn't be "Catholic schools" – they'd just be "schools". Maybe that's what the Catholic-bashing set wants – the evacuation of every smidgen of Catholic ideology from Catholic schools, so that they end up being indistinguishable from your average state school, and so that Catholic parents are denied the fundamental liberty to send their children to a school that embodies their values.

The irony is that while secularists accuse Catholic schools of "politically indoctrinating" their pupils, the real political indoctrination taking place here is the neverending attempt to prevent Catholic schools from imparting their values to their pupils. It is this intolerant desire to force Catholic schools to bend their knee to every mainstream political idea – whether it's on "safe sex" or "same-sex marriage" – which smacks of indoctrination, of attempting to cleanse institutions of the "wrong" way of thinking and make them repeat chattering-class catechisms.

The attempt to drain religious schools of religion is a highly illiberal, intolerant exercise. As Hannah Arendt argued more than 50 years ago: "To force parents to send their children to [a certain] school against their will means to deprive them of rights which clearly belong to them in all free societies – the private right over their children and the social right to free association." Today, forcing Catholic parents to send their children to schools which celebrated same-sex marriage, despite the fact that many of those parents don't like the idea of same-sex marriage, would represent a stinging attack on parents' rights over their children and on their right to "freely associate" with like-minded people.

This all goes to show how stiflingly conformist the idea of same-sex marriage has become, to such an extent that campaigners can't even let alone Catholic schools which argue against it. Maybe these schools should create priest holes, where they can safely uphold the virtues of traditional marriage away from the prying eyes of liberal indoctrinators.